is there any proof that these things do anything to help performance? I've yet to see anything

nope. I assume all the laptop manufacturers test their machines without these and design them to handle hot climates. Clearly, this is a waste, unless your machine has broken cooling and overheats...

If you swap your notebook HDD to something that generates more heat, this is a good solution.

these pads does help cool down laptops. i suppose ppl dont think they do anything bc, for instance, your laptop produces a minimum amount of heat regardless, say 39C. putting a cooling pad to lower the temp wont do anything bc 39C is the min. temperature. however, when you run programs that require more power, then the cooling pad will help lower the rising temperature. say if you play a game, instead of it being 59C, the pad will lower it to 50C.

Meritline likes to play with the price game, raise up the item price so they can offer bigger coupon. They do that ALL THE TIME just to fool consumers, I'd boycott them.